Lubricating compositions



Patented Mar. 5, 1946 2,396,223 LUBRICATING COMPOSITIONS v Carl F. Prutton, East Cleveland, Ohio, asslgnor to The Lubrl-Zol Corporation, Wlcklifle, Ohio, a

corporation of Ohio No Drawing. Application December 19, 1939, Serial No. 310,037

14 Claims.

ity and gum-forming tendencies which characterize similar lubricating compositions now commonly available.

This application is a continuation in part of copending application, Serial No. 737,070, filed July 26, 1934; Serial No. 193,960, filed March 4, 1938;

and Ser. No. 203,438, 'filed April 21, 1938.

By extreme pressures," as referred to above, is meant pressures of or in excess of 10,000 pounds per square inch, such'pressures now being commonly encountered in hypoid gears, bearings, contact surfaces of cylinders and piston rings in internal combustion engines, and many other points. Such pressures tend to cause the rupture of the continuous thick film of lubricant which separates bearing surfaces under more moderate conditions. A region of thin-film lubrication results which is also sometimes described as .boundary" lubrication.

It is a principal object of this invention, therefore, to provide a method of lubricating and a inbricating composition which will operate under conditions of extreme pressure to prevent seizure between the relatively moving metallic surfaces and which may be so employed without danger of deleterious effect upon the parts lubricated.

Other objects of this invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims; the following description setting forth in detail certain approved combinations of ingredients embodying my in,- vention, such disclosed means constituting, however, but certain of various forms in which the principle of the invention may be used.

Broadly stated, this invention comprises a method of lubricating and a lubricating composition wherein the reaction product of halogen bearing xylene having at least some of the halogen on an alkyl group with sulphur or a sulphur bearing reagent, including inorganic sulphides and polysulphides, is employed in conJunction with a hydrocarbon oil.

While for certain specialized uses the above defined additive may be employed as the sole lubricant this invention contemplates that in general, it will be employed as an addition agent to mineral lubricating oils in minor amounts ranging from about .2% to about 20% by weight, based on the amount of mineral oil. As ageneral rule, from about 1% to about 5% will be found to be an 5 effective and desirable proportion of the addition agent although larger amounts up to about or even 20% may be preferred for special uses. The final product should contain at least .2% of the addition agent in order that it may exhibit 10 sufficient extreme pressure properties to be commercially feasible.

While the oil base is referred to above as a mineral lubricating oil it is tobe understood that any other suitable hydrocbarbon lubricating oil,

whether naturally occurring or synthetic, may

be employed as the oil base.

It is also within the contemplation of this invention to provide the addition agent in the form of a concentrate in a'suitable oil, said oil containing rather large percentages of the addition agent. Such concentrates are employed for future blending with a lubricating oil in the pro- ,portions desired for the particular conditions of lguse.

a The said reaction products and especially dixylyl disulphide and dixylyl sulphide are particularly satisfactory addition agents to mineral oils because, in addition to their efiectiveness, they are relatively chemically inactive at ordinary temperatures and under ordinary pressures but under conditions of extreme pressure they will react with the relatively moving metallic surfaces to form an anti-fiuxlng film and prevent seizure and scoring of said surfaces. From a practical oils is another important advantage.

Dixylyl disulphide may be made by reacting chlor-xylene having at least some of the halogen on an alkyl group with NazSz. Dixylyl sulphide (di-methyl benzyl sulphide) may be similarly produced; for example, boiling xylene is chlorinated until the boiling point reaches 200 C. and the chlorinated xylene is then allowed to react with sodium sulphide in alcoholic solution. The product separates as a heavier oily layer and may be treated with calcium oxide at 100 C. to remove any remaining traces of unstable chlorine.

All of the halogens are suitable for use in accordance with this invention but chlorine is generally preferred to bromine, fluorine or iodine because of its effectiveness coupled with low cost and availability.

By "sulphur bearing reagent" as employed herein and in the claims is meant compounds of the 80 class consisting of the metallic sulphides and point of view their ready solubility in lubricatingpolysulphides, the ammonium sulphides and poly= sulphides, hydrogen sulphide and polysulphides, the inorganic xanthates and thlocyanates.

More specifically, these include such preferred examples as sodium sulphide, sodium disulphide, sodium hydrogen sulphide, ammonium sulphide, the corresponding hydrogen sulphides and polysulphides and the sodium and potassium xanthates and thiocyanates. When carrying out the reaction with the halogen bearing xylene it is often advantageous to employ the sulphur compound in anhydrous form and under pressure.

When still greater resistance to extreme pres-,

sure conditions is desired than that afiorded by the addition agent of this invention alone it may often be found advantageous to employ a small amount of a separate organic halogen compound which will cooperate with the addition agent of this invention to increase the film strength of the lubricant (as indicated on the Almen machine) to a degree greater than the sum of the efiects of either addition agent when used alone.

Examples of separate organic halogen compounds found particularly suitable include the following:

Fluorinated octane Chlorinated tributyl amine Ortho-dichlorbenzene Ortho-dibrombenzene Ethyl dichlorbenzene ca-MOIlO-ChlOI' naphthalene Methyl chlor salicylate Chlorinated diphenyl ether Chlorinated cyclohexanol Chlorinated dibutyl ketone The above list is intended to be illustrative only and not as a limitation upon the scope of the present invention.

Of course, if the halogen bearing Xylene has an appreciable proportion of halogen on the ring, this will generally be substantially unaffected by the reaction and the product will thus contain both sulphur and halogen. In such case it is seldom found necessary to further enhance the extreme pressure properties of the lubricant by the inclusion of a separate organic halogen compound although in some instances and for some applications this may still be desirable. Chlorxylyl disulphide and chlor-xylyl sulphide are par ticularly effective;

While the lubricating compositions which have been described herein as illustrating one embodiment of the invention have been generally referred to as oils, i. e., liquids, this invention is, however, also especially applicable to the solid and semi-solid types of lubricant commonly referred to in the trade as greases, bodied oils, etc., and which may contain soaps such as sodium, calcium, lead and aluminum naphthenates, stearates and oleates.

The following table shows the results obtained when testing various percentages of dixylyl disulphide in mineral oil on the SAE machine:

The untreated mineral oil shows practically no ability to resist the Pressures applied by this machine and the remarkable efiectiveness oi the addition agent is clearly shown by the above table.

. The base oil employed is a refined SAE 160 base oil.

On the Almen machine the following results were obtained:

1 The mark indicates that the lubricant withstood the most severe load the machine could apply.

While mineral oil generally is the principal ingredient of the lubricant, it is not essential that it be the only ingredient other than the addition agent, provided that there be no additional ingredient which is incompatible with such addition agent. It is within the contemplation of this invention to include, if necessary or desirable, such other addition agents as are commonly added to improve the viscosity index or cold test of the lubricant and a lubricating composition according to this invention which also has a separate oiliness increasing agent has been found to be especially eilective.

Other modes of applying the principle of the invention may be employed, change bein made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. An extreme pressure lubricating composition comprising a major proportion of mineral oil and a minor amount of the reaction product of halogen-bearing xylene having at least some of the halogen on an alkyl group, and a reagent from the class consisting of sulphur, the metallic sulphides and polysulphides, the ammonium sulphides and polysulphides, hydrogen sulphide and polysulphides, and the inorganic xanthates and thiocyanates, whereby at least a portion of the sulphur in the end product is on an alkyl group.

2. An extreme pressure lubricating composition comprising a major proportion of mineral oil and a minor amount of the reaction product of chicrine-bearing xylene having at least some of the chlorine on an alkyl roup, and a reagent from the class consisting of sulphur, the metallic sulphides and polysulphides, the ammonium sulphides and polysulphides, hydrogen sulphide and polysulphides, and the inorganic xanthates and thiocyanates, whereby at least a portion of the sulphur in the end product is on an alkyl group.

3. An extreme pressure lubricating composition comprising a major proportion of mineral oil and a minor amount or the reaction product of halogen-bearing xylene having at least some of the halogen on an alkyl group, and an inorganic polysulphide, whereby at least a portion of the sulphur in the end product is on an alkyl group.

4. An extreme pressure lubricating composition comprising a major proportion of mineral oil and from an effective amount to 20% of the reaction product of halogen-bearing xylene having at least some of the halogen on an alkyl group, and an inorganic polysulphide, whereby at least a portion of the sulphur in the end product is on an alkyl group.

- group.

6. An extreme pressure lubricating composition comprising a major proportion of mineral oil and a minor amount of chlor-xylyl disulphide, with a substantial proportion of the halogen pres: ent in the nucleus.

7. An extreme pressure lubricating composition comprising a major proportion of mineral oil, anda minor amount of the reaction product of xylyl chloride with an inorganic polysulphide, whereby at least a portion of th sulphur in the end product is on an alkyl group. i

8. An extreme pressure lubricating composition comprising a major proportion of mineral oil the film strength of which has been substantially increased by the inclusion therein of a minor proportion of a dixylyl disulphide of the type in which at least a portion of the sulphur is on an alkyl group.

9. An extreme pressure lubricating composition comprising a'major proportion of mineral oil the film strength of which has been substantially increased by the inclusion therein of from an effective amount to 20% of a dixyiyl disulphide of the type in which at least a portion of the sulphur is on an alkyl group.

10. An extreme pressure lubricating composition comprising a major proportion of mineral oil the film strength of which has been substantially increased by the inclusion therein 01 from about .2% to about 10% of a dixylyl disulphide of the type in which at least a portion of the sulphur is on an alkyl group.

11. An extreme pressure lubricating composition comprising a major proportion pt mineral oil the film strength of which has been substantially increased by the inclusion therein of from about 1% to about 5% of a dixyly1 disulphide of the type in which at least a portion of the sulphur is on an alkyl group.

12. An extreme pressure lubricating composition comprising a major proportion of mineral oil and a minor amountof a xylyl sulphide of the type in which at least a portion of the sulphur is on an alkyl group. v

13. An extreme pressure lubricating composition comprising a major proportion of mineral oil and a. minor amount of chlor-xylyl sulphide, with a substantial proportion of the halogen present in the nucleus, said sulphide being of the type in which at least a portion of the sulphur is on an alkyl group.

14. An extreme pressure lubricating composition comprising a major proportion of mineral oil the film strength of which has been substantially increased by the inclusion therein of a minor proportion of a xylyl disulphide of the type in which atleast a portion of the sulphur is on an alkyl group.

CARL F. PRU' ITON. 

